1. Field of the Invention
This disclosure relates to a liquid discharge head.
2. Description of the Related Art
Examples of known liquid discharge heads used in an inkjet type recording apparatus include a liquid discharge head having a substrate and a heat resistor layer on the substrate. The liquid discharge head having the heat resistor layer generates air bubbles in liquid in a pressure chamber by heating a heat effect portion of the heat resistor layer and discharge liquid from a discharge port.
Japanese Patent Laid-Open No. 2010-120389 discloses a liquid discharge head having the heat effect portion of a heat generating resistor formed at a position apart from the substrate. Energy generating at the heat effect portion is sufficiently transferred to liquid in a pressure chamber by forming the heat effect portion at the position away from the substrate. A schematic drawing of the liquid discharge head as described above is illustrated in FIG. 2A. A wiring 2 is formed on a substrate 1, and an insulation layer 3 and a heat resistor layer 5 are formed thereon. A portion of the heat resistor layer 5 located in in a pressure chamber 11 corresponds to a heat effect portion. The heat effect portion is formed in a hollow shape and located at a position away from the substrate 1 in the pressure chamber 11. A side wall of the pressure chamber 11 is formed of a side wall member 7. In FIG. 2A, a discharge port 10 is also formed in the side wall member 7. The discharge port 10 is positioned above the heat effect portion of the heat resistor layer 5. A surface of the side wall member 7 where the discharge port 10 opens is covers with a surface protecting layer 9. The side wall member 7 is formed of a film of an inorganic material, and a space formed between the side wall member 7 and the substrate 1 is filled with a filling material 6.
A side wall member of the liquid discharge head described in Japanese Patent Laid-Open No. 2010-120389 is formed of an inorganic material. When the side wall member is formed of the inorganic material, the resistance characteristics of the side wall member against liquid may be improved. In addition, a reduction of the thickness of the side wall member is easily achieved.